Many garden experts say that the flowers of plants, except for hydrangeas, cannot change color.

Big-leaf hydrangeas, the ones with large showy flowers (actually bracts), are thought to stand alone in the ability to change bloom color. In acidic soil (pH below 5.5), hydrangeas produce blue flowers. In neutral to alkaline soils (pH of 6.5 and higher), flowers are usually pink, supposedly because higher pH makes aluminum in the soil unavailable to the plant. My experience is that changing the color of these plants by adjusting soil amendments is possible, but mostly the results turn out to be a rather dull color somewhere between blue and pink.

Related to other plants, some horticultural experts say it's just a figment of the imagination that flowers can change color, that it doesn't happen in nature and can't happen in your garden. But that's not true. Flowers can definitely change color, but it is a little difficult to explain how it happens.

Doubters will say that if an iris or any other plant changes color, it could be a combination of things or simply a random accident, but it's not the plant actually changing color. Attempted explanations range from a rogue rhizome of white irises getting in the blue/purple iris bed and taking over, to you just forgetting what you planted and where.

Bright pink crinum lilies changed colors to white with pink stripes and for the last five seasons they have bloomed a beautiful pure white.

(Howard Garrett)

Some will admit that flowers can have a slight color change or loss of color due to extreme temperature changes or a change in light conditions because the nearby trees got bigger. Deep purple irises commonly turn a lighter color when maturing and starting to die. It is also said that these color changes usually revert back over time, and the plant will resume its usual color.

Unexplained instances of an entire bed that was purple turning white the following year just can't happen, they say. But it can. It happened at my office. When we bought the place, the iris bed in the front yard was all blue/purple. The next year it was all solid white, and I didn't do anything to the bed other than start fertilizing with the organic fertilizers I generally use.

Several of my listener/readers have reported similar cases and results. My buddy and co-organic-conspirator on the radio in San Antonio, Bob Webster, has had personal experience and many reports from others about this curious flower color change.

The case that confirmed my strong suspicions happened in my own backyard. Bright pink crinum lilies were planted in early spring and bloomed that first summer with gaudy hot pink flowers. The next season they were white with pink stripes, and for the last five seasons they have bloomed a beautiful pure white.